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Galeus Arae
The roughtail catshark or marbled catshark (''Galeus arae'') is a common species of catshark, part of the family Scyliorhinidae. It is found at a depth of in the northwestern Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea, from North Carolina to Costa Rica. Individuals of different sexes and ages are segregated to some degree. A small species not exceeding in length, the roughtail catshark has a slender body with a marbled color pattern of dark saddles and spots, and a prominent crest of enlarged dermal denticles along the dorsal edge of its caudal fin. This species feeds mainly on shrimp and is oviparous. It is caught incidentally in shrimp trawls, though trawl fisheries within its range mostly do not operate at the depths it inhabits. As a result, the International Union for Conservation of Nature has listed it under Least Concern. Taxonomy John T. Nichols of the American Museum of Natural History originally described the roughtail catshark as ''Pristiu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Treadwell Nichols
John Treadwell Nichols (June 11, 1883 – November 10, 1958) was an American ichthyologist and ornithologist. Life and career Nichols was born in Jamaica Plain, Boston, Massachusetts, the son of Mary Blake (Slocum) and John White Treadwell Nichols. In 1906 he studied vertebrate zoology at Harvard College, where he graduated with a Bachelor of Arts (AB). In 1907 he joined the American Museum of Natural History as assistant in the department of mammalogy. In 1913 he founded ''Copeia'', the official journal of the American Society of Ichthyologists and Herpetologists The American Society of Ichthyologists and Herpetologists (ASIH) is an international learned society devoted to the scientific studies of ichthyology (study of fish) and herpetology (study of reptiles and amphibians). The primary emphases of the .... In 1916 he described the long lost Bermuda petrel together with Louis L. Mowbray, Louis Leon Arthur Mowbray who first sighted this bird within a flock of other petrel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Least Concern
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. They do not qualify as threatened, near threatened, or (before 2001) conservation dependent. Species cannot be assigned the "Least Concern" category unless they have had their population status evaluated. That is, adequate information is needed to make a direct, or indirect, assessment of its risk of extinction based on its distribution or population status. Evaluation Since 2001 the category has had the abbreviation "LC", following the IUCN 2001 Categories & Criteria (version 3.1). Before 2001 "least concern" was a subcategory of the "Lower Risk" category and assigned the code "LR/lc" or lc. Around 20% of least concern taxa (3261 of 15636) in the IUCN database still use the code "LR/lc", which indicates they have not been re-evaluate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill Slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of cartilaginous fish such as sharks and rays, as well as deep-branching vertebrates such as lampreys. In contrast, bony fishes have a single outer bony gill covering called an operculum. Most sharks and rays have five pairs of gill slits, but a few species have 6 or 7 pairs. Shark gill slits lie in a row behind the head. The anterior edge of a gill slit is motile, moving outward to allow water to exit, but closing to prevent reverse flow. A modified slit, called a spiracle, lies just behind the eye, which assists the shark with taking in water during respiration and plays a major role in bottom–dwelling sharks. Spiracles are reduced or missing in active pelagic sharks. While the shark is moving, water passes through the mouth and over the gills in a process known as "ram ventilation". While at rest, most sharks pump water over their gills t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiracle (vertebrates)
Spiracles () are openings on the surface of some animals, which usually lead to respiratory systems. The spiracle is a small hole behind each eye that opens to the mouth in some fish. In the jawless fish, the first gill opening immediately behind the mouth is essentially similar to the other gill opening. With the evolution of the jaw in the early jawed vertebrates, this gill slit was caught between the forward gill-rod (now functioning as the jaw) and the next rod, the hyomandibular bone, supporting the jaw hinge and anchoring the jaw to the skull proper. The gill opening was closed off from below, the remaining opening was small and hole-like, and is termed a spiracle. In many species of sharks and all rays the spiracle is responsible for the intake of water into the buccal space before being expelled from the gills. The spiracle is often located towards the top of the animal allowing breathing even while the animal is mostly buried under sediments. As sharks adapted a faster ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nictitating Membrane
The nictitating membrane (from Latin '' nictare'', to blink) is a transparent or translucent third eyelid present in some animals that can be drawn across the eye from the medial canthus to protect and moisten it while maintaining vision. All Anura(tailless amphibians), and some reptiles, birds, and sharks have full nictitating membranes; in many mammals, a small, vestigial portion of the nictitating membrane remains in the corner of the eye. Some mammals, such as cats, camels, polar bears, seals and aardvarks, have full nictitating membranes. Often called a third eyelid or haw, it may be referred to in scientific terminology as the ''plica semilunaris'', ''membrana nictitans'', or ''palpebra tertia''. Description The nictitating membrane is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten it while maintaining vision. The term comes from the Latin word '' nictare'', meaning "to blink". It is o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species Complex
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synonymously but have more precise meanings are cryptic species for two or more species hidden under one species name, sibling species for two (or more) species that are each other's closest relative, and species flock for a group of closely related species that live in the same habitat. As informal taxonomic ranks, species group, species aggregate, macrospecies, and superspecies are also in use. Two or more taxa that were once considered conspecific (of the same species) may later be subdivided into infraspecific taxa (taxa within a species, such as bacterial strains or plant varieties), that is complex but it is not a species complex. A species complex is in most cas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Springer's Sawtail Catshark
Springer's sawtail catshark (''Galeus springeri'') is a species of catshark, belonging to the family Scyliorhinidae, found in waters deep off the islands of the Antilles, from Cuba to the Leewards. A small, slim-bodied species reaching a length of , the Springer's sawtail catshark can be identified by its color pattern of horizontal dark stripes in front of the first dorsal fin, and dark dorsal saddles behind. It is additionally characterized by the presence of saw-toothed crests, made of enlarged dermal denticles along both the dorsal and the ventral edges of the caudal fin. The Springer's sawtail catshark is oviparous. Taxonomy The Springer's sawtail catshark was originally regarded as the striped color morph of the Antilles catshark (''G. antillensis'', formerly ''G. arae antillensis''). The first known specimen had resided in the National Museum of Natural History for over 20 years, until an artifact of preservation revealed the distinctive ventral dermal denticle crest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern Sawtail Catshark
The southern sawtail catshark (''Galeus mincaronei'') is a species of catshark, part of the family Scyliorhinidae, endemic to southern Brazil. It inhabits deepwater reefs on the upper continental slope at a depth of . Reaching at least in length, this slim-bodied species closely resembles the Antilles catshark (''G. antillensis''). It has a prominent crest of enlarged dermal denticles along the dorsal edge of the caudal fin, as well as a distinctive color pattern of dark oval blotches, outlined in white, along its back. The southern sawtail catshark is oviparous, with females producing reddish egg capsules. The International Union for Conservation of Nature (IUCN) has assessed it as Vulnerable; it is often taken as bycatch and may be threatened by intensifying squid fishing. Taxonomy The first known specimens of the southern sawtail catshark were caught in a series of experimental fish traps set off Rio Grande do Sul, Brazil, in 1988. Initially identified as ''Galeus antille ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species have subspecies, but for those that do there must be at least two. Subspecies is abbreviated subsp. or ssp. and the singular and plural forms are the same ("the subspecies is" or "the subspecies are"). In zoology, under the International Code of Zoological Nomenclature, the subspecies is the only taxonomic rank below that of species that can receive a name. In botany and mycology, under the International Code of Nomenclature for algae, fungi, and plants, other infraspecific ranks, such as variety, may be named. In bacteriology and virology, under standard bacterial nomenclature and virus nomenclature, there are recommendations but not strict requirements for recognizing other important infraspecific ranks. A taxonomist decides whether ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longfin Sawtail Catshark
The longfin sawtail catshark (''Galeus cadenati'') is a rare, little-known species of catshark, part of the family Scyliorhinidae. Once thought to be a subspecies of the roughtail catshark (''G. arae'') along with the Antilles catshark (''G. antillensis''), it inhabits deep water off the Caribbean coasts of Panama and Colombia. This slim-bodied species has a marbled dorsal color pattern and a prominent crest of enlarged dermal denticles along the dorsal edge of its caudal fin. It can be distinguished from similar species by its relatively longer anal fin and small adult length of under . The longfin sawtail catshark is oviparous. Taxonomy Renowned shark expert Stewart Springer described the longfin sawtail catshark in a 1966 issue of the ''United States Fish and Wildlife Service Fishery Bulletin'', based on a long female collected off Panama on May 30, 1962. He named the species after French zoologist Jean Cadenat, who described the similar African sawtail catshark (''G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antilles Catshark
The Antilles catshark (''Galeus antillensis'') is a common but little-known species of catshark, part of the family Scyliorhinidae. It is found on or near the bottom at a depth of off Florida and the West Indies from Jamaica to Martinique. It was once regarded as a subspecies of the similar roughtail catshark (''G. arae''), along with the longfin sawtail catshark (''G. cadenati''). Growing to long, the Antilles catshark is a slender species with a marbled color pattern of dark saddles and blotches, as well as a crest of enlarge dermal denticles along the front part of its dorsal caudal fin margin. It feeds on shrimp and may have schooling habits. Reproduction is oviparous. Taxonomy Shark expert Stewart Springer first described the Antilles catshark as an island subspecies of ''G. arae'' in a 1979 National Oceanic and Atmospheric Administration (NOAA) Technical Report. The type specimen was collected off Saint Kitts in the Leeward Islands.Springer, S. (April 1979). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galeus
''Galeus'' is a genus of catshark, belonging to the family Scyliorhinidae, commonly known as sawtail catsharks in reference to a distinctive saw-toothed crest of enlarged dermal denticles, found along the upper edges of their caudal fins. They are found in the Atlantic, the western and central Pacific, and the Gulf of California, inhabiting deep waters at or close to the sea floor. Members of this genus are rather small, slim sharks with firm bodies and thick, rough skin. Their heads are usually fairly long and pointed, and have large mouths with well-developed furrows at the corners. They have large pectoral and anal fins, and two similar dorsal fins placed well back. Many species are ornately patterned with dark saddles and/or blotches. Sawtail catsharks feed on various invertebrates and fishes, and may be either egg-laying or live-bearing. These harmless sharks are sometimes caught as bycatch but are of minimal commercial value. Taxonomy ''Galeus'', derived from the Greek ''g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
